Nucleation-free gap fill ALD process

Abstract

Processing methods comprise forming a gap fill layer comprising tungsten or molybdenum by exposing a substrate surface having at least one feature thereon sequentially to a metal precursor and a reducing agent comprising hydrogen to form the gap fill layer in the feature, wherein there is not a nucleation layer between the substrate surface and the gap fill layer.

The invention claimed is: 
     
       1. A processing method comprising:
 exposing a substrate surface having at least one feature thereon to a first metal precursor comprising one or more of a titanium precursor, an aluminum precursor, and a silicon precursor, and a reactant comprising a nitrogen precursor to form an underlying layer comprising TIN, TiSiN, AlN, or TiAlN; 
 exposing the underlying layer to air to form surface oxidation; 
 applying a chemical treatment to the underlayer to remove the surface oxidation and form a treated surface; and 
 forming a gap fill layer on the treated surface using an atomic layer deposition (ALD) process by sequentially exposing the treated surface to a second metal precursor comprising tungsten or molybdenum and a reducing agent comprising hydrogen to form the gap fill layer in the feature, wherein there is not a nucleation layer between the treated surface and the gap fill layer. 
 
     
     
       2. The processing method of  claim 1 , wherein the second metal precursor is one or more of WF 6 , WCl x , W(CO) 5 , MoF 6 , MoCl x , where x is 5 or 6, and the reducing agent is H 2 . 
     
     
       3. The processing method of  claim 1 , wherein the treated surface is not exposed to air prior to forming the gap fill layer. 
     
     
       4. The processing method of  claim 1 , wherein the chemical treatment comprises exposing the substrate surface to one or more of the following:
 Si x H 2x+2 , wherein x>=1; 
 SixHyFz, wherein x>=2 and y+z=2x+2; 
 SixHyClz, wherein x>=2 and y+z=2x+2; 
 BxHy, wherein x>=2 and y<=2x+2; 
 BxHyClz, wherein x>=2 and y+z<=2x+2; 
 BxHyFz, wherein x>=2 and y+z<=2x+2; and 
 B x H y R z , wherein x>=2, y+z<=2x+2, and R comprises an alkyl group having 1 to 6 carbons. 
 
     
     
       5. The processing method of  claim 1 , wherein forming the gap fill layer comprises sequentially exposing the treated surface such that reactive gases of the second metal precursor and the reducing agent are separated from mixing. 
     
     
       6. The processing method of  claim 1 , wherein forming the gap fill layer comprises sequentially exposing the treated surface such that gas phase reactions between the second metal precursor and the reducing agent are reduced or prevented. 
     
     
       7. The processing method of  claim 1 , wherein the underlying layer is formed using an atomic layer deposition (ALD) process. 
     
     
       8. A processing method comprising:
 sequentially exposing a substrate surface having at least one feature thereon to a first metal precursor and a reactant to form an underlying layer, wherein the first metal precursor comprises a titanium precursor and the reactant comprises a nitrogen precursor; 
 exposing the underlying layer to air to form surface oxides thereon;
 applying a chemical treatment to the underlying layer to remove surface oxides and form a treated surface; and 
 
 exposing the treated surface sequentially to a second metal precursor comprising a tungsten precursor or a molybdenum precursor, and a reducing agent comprising hydrogen (H 2 ) to form a gap fill layer on the treated surface using an atomic layer deposition (ALD) process, wherein there is not a nucleation layer between the treated surface and the gap fill layer. 
 
     
     
       9. The processing method of  claim 8 , wherein the reducing agent consists essentially of hydrogen (H 2 ). 
     
     
       10. The processing method of  claim 8 , wherein the second metal precursor is one or more of WF 6 , WCl x , W(CO) 5 , MoF 6 , MoCl x , where x is 5 or 6. 
     
     
       11. The processing method of  claim 8 , wherein the treated surface is not exposed to air before forming the gap fill layer. 
     
     
       12. The processing method of  claim 8 , wherein the chemical treatment comprises exposing the underlying layer to one or more of the following:
 Si x H 2x+2 , wherein x>=1; 
 SixHyFz, wherein x>=2 and y+z=2x+2; 
 SixHyClz, wherein x>=2 and y+z=2x+2; 
 BxHy, wherein x>=2 and y<=2x+2; 
 BxHyClz, wherein x>=2 and y+z<=2x+2; 
 BxHyFz, wherein x>=2 and y+z<=2x+2; and 
 BxHyRz, wherein x>=2, y+z<=2x+2, and R comprises an alkyl group having 1 to 6 carbons. 
 
     
     
       13. The processing method of  claim 8 , wherein the underlying layer comprises TiN. 
     
     
       14. The processing method of  claim 8 , wherein forming the gap fill layer comprises sequentially exposing the treated surface such that reactive gases of the second metal precursor and the reducing agent are separated from mixing. 
     
     
       15. The processing method of  claim 8 , wherein forming the gap fill layer comprises sequentially exposing the treated surface such that gas phase reactions between the second metal precursor and the reducing agent are reduced or prevented. 
     
     
       16. The processing method of  claim 8 , wherein the underlying layer is formed using an atomic layer deposition (ALD) process.